A variety of devices have been developed to detect sounds produced by the body, such as heart sounds. Known devices range from primarily mechanical devices, such as the stethoscope, to various electronic devices, such as microphones and transducers. The stethoscope, for example, is a fundamental tool used in, the diagnosis of diseases and conditions of the cardiovascular system. It serves as the most commonly employed technique for diagnosis of such diseases and conditions in primary health care and in circumstances where sophisticated medical equipment is not available, such as remote areas.
Although many electronic stethoscopes are available on the market, they have yet to gain universal acceptance by the physicians and other medical practitioners. Possible reasons for non-acceptance of electronic stethoscopes include the production of noise or artifacts that disturb the clinician during patient evaluation, as well as limitations associated with amplification and reproduction of certain biological sounds of interest. For example, a biological sound may be present but masked by noise, or wholly absent, and many conventional electronic stethoscopes are not capable of distinguishing between these two cases.
Noise that impacts stethoscope performance may be defined as any signal other than that of interest. Various types of noise include external or ambient noise, noise related to auscultation, noise generated by the electronic circuits of the stethoscope, and noise of biological nature produced by the patient's body, for example.
There is a need for a bioacoustic sensor with improved sensitivity and robustness. There is a further need for such a sensor that may be incorporated in various types of medical sensing devices, such as stethoscopes, that provides for an improved signal-to-noise ratio relative to conventional implementations. The present invention fulfills these and other needs.